The present invention relates to uninterruptible power supply (“UPS”) systems, and more particularly to the input circuitry of UPS systems. The universal UPS input circuitry of the present invention can be used with essentially any UPS system to support any suitable type of backup power system commonly used with uninterruptible power supplies.
Utility companies typically provide regulated power to loads present on the utility's distribution network. Sometimes, however, the requisite power is not provided for a particular load. This can be caused, for example, by a blown transformer or downed power lines or other outage. In these instances, the load may receive power that is insufficient to sustain normal operation or it may not receive power at all. The lull in power may last for a few seconds or for days, depending on the severity of the utility supply problem. Therefore, UPS systems have been developed to ensure that continuous supply of regulated power is provided to a load. UPS systems typically operate in two different modes, normal mode and backup mode, both of which are discussed in more detail below.
In a typical UPS system, utility power is provided to the load during normal mode operation. In normal mode operation, the UPS system monitors the quality (e.g., frequency, harmonic distortion, etc.) and the quantity (e.g., magnitude of voltage, current, and power) of utility power provided to the load. During this mode, the UPS system provides power to the load that is substantially regulated to predetermined limits set for utility power distribution. In addition, during normal mode, the UPS system may provide utility power to a backup system. Providing power to a backup system may ensure that it is constantly prepared to enter backup mode operation. When the power provided by the utility falls outside the predetermined limits, the UPS system may switch from normal mode operation to backup mode operation.
In backup mode operation, the UPS system draws power from a backup system and provides it to the load. The UPS system may continuously utilize the backup system to provide power to the load until the utility power is restored. In prolonged utility failures, the UPS system may have to switch between two or more backup systems to provide adequate power to the load. Multiple backup systems may be used to provide both short and long term backup power. One backup system may, for example, provide essentially instantaneous power for a short period of time (e.g., fifteen seconds). Another backup system may be used to provide backup power for longer periods of time (e.g., several days), but not instantaneous power to the load. During backup mode, the power drawn from the backup system may be converted or modified (e.g., the system may change a DC signal to an AC signal) to obtain the desired signal for the load. When utility power is restored, the UPS system may revert back to normal mode operation, thus ceasing the draw of power from the backup system.
There are several different types of backup power systems in which a UPS system may rely on for backup power. This can present difficulties in installation or result in complex setup procedures because each type of backup system may operate using a specific set of parameters, which the UPS system must control or adhere to in order to function properly. For example, whenever a backup system is installed with a UPS system, the UPS system may have to take into account parameters such as AC or DC generated signals, varying ranges of output voltage. If an AC backup system is used, varying ranges in frequency must be accounted for, and the duration of which the system can provide power to a particular load may also differ, as well as various other suitable parameters.
When a user adds or replaces a UPS system that is operating in conjunction with an existing backup power system, the new UPS system may have to undergo extensive re-configurations. For example, if the existing backup power system is a manually operated diesel power generator, a newly added UPS system may require extensive setup time to operate in conjunction with that generator. Furthermore, UPS system configuration may be made even more difficult if the user is installing a UPS system that automatically monitors the generator (e.g., power output).
In view of the foregoing, it is an object of this invention to provide universal UPS input circuitry that readily accepts any type of backup system for use in a UPS system.
It is also an object of this invention to utilize software that configures the universal UPS input circuitry to operate in conjunction with the backup system.